What you are looking for is a cable swager. They are very common in medium to large aircraft repair shops. They are used to swage stops and fittings on aircraft control cables from 1/16th inch to 3/8ths inch cable.
Locally you can find some hand swager tools at hardware stores. Not as high grade as what the fly-boys use, but adequate.
Alternately, try a local rancher that is using high tensil wire fencing for livestock. The swage tool used for this type fence looks like a big set of bolt cutters, and the swage splices supplied are available in different diameters.
Also, linemen for power companies use a hand swage tool in their work that is similar to what the ranchers use. Again, different size "crimps" are available.
If all the above fails, try the local archery shop. They swage stops on bow cables (but I think their stuff will be too small).
Carter BBD feeding 4.2 Nuttered 6 banger = 22 MPG Hwy
If it was easy, everyone would be doing it.